let data = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15"];
$ui.render({
  views: [
    {
      type: "list",
      props: { data },
      layout: $layout.fill,
      events: {
        didReachBottom: function(sender) {
          $ui.toast("fetching...")
          $delay(1.5, () => {
            sender.endFetchingMore()
            data = data.concat(data.map(item => {
              return (parseInt(item) + 15).toString()
            }))
            $("list").data = data
          })
        }
      }
    }
  ]
})